7 / 2019-01-15 07:09:01

Passive Capacitor Stacking to Improve Integrated Circuit Power Supply Decoupling

power distribution network; integrated circuit packaging; impedance measurement; power supply decoupling

This paper introduces and tests a novel method of integrated circuit (IC) power distribution network (PDN) improvement. This is achieved by using stacked passive components on an IC die to improve circuit performance by providing local power supply decoupling. These stacked passives are orders of magnitude greater than what is available for in substrate integration. The capacitors reduce PDN impedance resulting in lower system noise on the device’s power supply rails. As the passive devices are located on top of the die, they are not impacted by bond wires or solder bumps which would lessen the effectiveness of package or printed circuit board mounted decoupling capacitors. The capacitors take no additional internal layer real estate in the target IC. A test fixture is developed and tested from 100kHz to 100MHz. A 130% noise decrease is shown at 100MHz when comparing on die decoupling to a package level decoupling solution.